Regionalism of the Bolivian highlands to refer to domesticated rodents also called "cuis" or "cobayas". The diminutive "cuisito" is also used for the offspring of these animals.
It is really rubbish this. It has no meaning, but I managed to find is as an acronym that used students for short courses of ISO in their class schedules. The truth is so silly that it does not deserve to use as meaning. They made reference to courses of ISO 9000 and ISO 14000.
cuiso is incorrectly written, and should be written as "cuis" being its meaning: Possibly a mistake of typing by " cuis ".
No seems nor so even exist and therefore, not has any meaning known as says Ricardo Forno. Perhaps it was intended to tell care, that the first person singular of the verb would be taking care of.
There seems to be a known meaning.